For example, we could be out exploring space with giant mechas, terraforming dead planets, fighting aliens from our galaxy, all the goodies.

Well, this kinda doesn't fit history. Didn't you know that the Space Race was part of the Cold War and originally dragged from World War II?

If you don't learn to live together as countries first there's no point unifying anything. Just look at the European Union. And North America, didn't the US want to build a giant wall?

I concur, regarding the Space Race. While the Cold War itself ended up being mostly economic (proxy wars aside) in nature, technology in general boomed through much of the Western world. Some of this was due to a combination of propaganda and sheer paranoia, but it still led us to where we are now.

As far as isolationist tendencies, the US had a lot of people pushing for them before both WWI and WWII. Much of this was along the lines of anti-immigration policies, but it's fair to say outright racism (and the roots of so-called "American exceptionalism" a.k.a. nationalism to the point of being intentionally ignorant of, and distorting of one's own history) were factors as well.

Ironically, the Star Trek universe also came to prominence during the Cold War, showing that humanity could move beyond both racism and extreme nationalism. For as much of a fan of it as I am, I don't hold it as an ideal for society. Well, close, but not quite. The later series indicated that while many of our planet's issues have been solved, there will always be greedy bastards trying to exploit everyone else. There will always be isolationists, and those obsessed with thought controlling others. Call it trading one set of issues for another.

Thus, an ideal society in my view would eliminate hunger and the need to fight over resources. It would be socialist in nature, and capitalism would need to be phased out eventually. Capitalism is one of the greatest dividing factors in human society, by its very nature. People would be free (and encouraged) to pursue whatever educational or career goals interest them, with a strong focus on technological innovation. Expansion into space would obviously be an important part of this, as it will eventually reduce overcrowding. Maintaining a balance between the expansion of technology and the environment is also a key point. Don't want to work towards a better society for all? You don't have to; but the pursuit of this should be its own reward.

An anarchist world where everyone is free to do whatever they want. I'm a devout anarchist. I imagine if anarchy existed in a multicultural countries, especially in a much developed Western countries, would others commit crimes against other races or would it be something worse like KKK or the Nazis?

I'm not being racist by pointing out KKK and Nazis, I was just pointing out minorities that existed in the human race.

Utopia of course, conflicts or war are cause by scarcity so a perfect world will be filled with abundancy so molecular assemblers like replicators is the ultimate fantasy

A fantasy is correct word , to bad people will always have their own self interest and rules in mind. People who believe in this kind of nonsense should really look out for themselves demand their own rights and free will , thats all people can really do regulating society just breeds tyrants cause there is always that temptation for control.

every1 is happy no1 can ever die inless u your self chooses to die freedom of speech freedom to do as you please accept rape and you can live on any planet any country basically anywhere you want no religion people fight for fun no governments kings queens or presidents complete fun freedom and every 1 is highly intelligent and very peaceful

every1 is happy no1 can ever die inless u your self chooses to die freedom of speech freedom to do as you please accept rape and you can live on any planet any country basically anywhere you want no religion people fight for fun no governments kings queens or presidents complete fun freedom and every 1 is highly intelligent and very peaceful